ISOLATION AND CHARACTERIZATION OF A POSSIBLE PATHOGENIC AGENT RESPONSIBLE FOR MORTALITY IN TADPOLES OF Rana catesbeiana Shaw, 1802.

Abstract

This study aimed isolating and characterizing the pathogen responsible for the mortality of Rana catesbeiana tadpoles that occurred in the Experimental Aquaculture Center of São Paulo State University (Unesp), Campus of Jaboticabal, Brazil. During a mortality outbreak, twenty tadpoles presenting prostration, anorexia, and dried and swollen skin were killed and submitted to post-mortem examination. Heart, liver, abdominal cavity, and bowel samples were aseptically collected. The materials were plated onto a selective medium for different bacteria. Colonies characteristic of Escherichia coli were seen in dishes with EMB and Mac Conkey selective mediums. Biochemical series identified and characterized the presence of E. coli. Strains obtained from isolated colonies were plated onto Petri dishes with Blood Agar, resulting in hemolysis, which is a characteristic of pathogenic bacteria. Therefore, E. coli could be ascribed as one of the responsible agents for the death outbreak. KEY -WORDS: Rana catesbeiana. Escherichia coli. Mortality.